Add a new helper method to be able to remove events listeners

[jfelip937]

To be able to remove all listeners of a type/types given an element/array/query selector.

As we already have the on method it will be consistent to have a method to remove the listeners.

PROPOSED SOLUTION

To remove a specific eventListener:

unbind(elements, events, function)

To remove all eventListeners:

unbind(elements, events)

Arguments:

• elements: Element / Array of Elements / Query selector
• events: String with the type of events to remove
• function: eventListener to be removed. If not added all eventListeners of the given types will be removed.